Adjustment of mobility parameters for traffic steering in multi-RAT multi-layer wireless networks

Mobile broadband traffic has been increasing in the last years. To cope with such traffic demand, heterogeneous networks are an effective solution characterized by deploying networks with different cell sizes, radio access technologies (RATs) and carrier frequencies. Since the coverage area of these networks (or layers) is partially overlapped, users can be steered to a specific layer in order to improve network performance. In this work, two mechanisms of traffic steering are analyzed in a realistic high-speed packet access/long-term evolution deployment scenario, where the objective is to offload traffic from the macro-layer to pico-cells. In idle mode, i.e., the state in which no dedicated resources have been established for the user, a static adjustment of the layer priorities in the cell reselection algorithm is performed. In connected mode, where dedicated resources have been established, the parameters of the inter-RAT handover triggering condition are statically adjusted to offload the macro-layer. Simulation results show that further offloading can be achieved by modifying these algorithms so that user satisfaction is improved.